The invention relates to a reflector lamp in accordance with the preamble of patent claim 1.
Such a reflector lamp is described, for example, in European laid-open specification EP 0 780 884 A1. This specification discloses a lamp reflector unit with a metal spring which is fitted on the lamp and rests on the reflector. The lamp is fixed in the reflector with the aid of this mechanically stressed metal spring. This reflector lamp is a pin-type socket lamp.
It is the object of the invention to provide a reflector lamp which is fitted with a screw base and which ensures reliable holding and making of electric contact with the lamp in the reflector with the simplest possible means.
This object is achieved according to the invention by means of the features of patent claim 1. Particularly advantageous designs of the invention are described in the dependent claims.
The reflector lamp according to the invention has a reflector which has a reflector neck and defines a reflector axis, as well as an electric lamp which is fixed in the reflector neck by means of a metallic holder, in which
a section of the metallic holder is arranged, secured against rotations about the reflector axis, in a cutout in the reflector neck and projects from the reflector neck through this cutout,
there is arranged in the region of the reflector neck a shoulder which is designed as a depth stop for the metallic holder in the direction of the reflector axis,
the reflector lamp has a metallic base shell which is provided with a thread and for which the outer wall of the reflector neck forms a stop surface, and
there is a screwed connection between the base shell and the part, projecting from the reflector neck, of the section, arranged in the cutout of the reflector neck, of the metallic holder.
The metallic holder of the reflector lamp according to the invention is arranged securely against rotation in the reflector neck, and coordinated with the reflector neck and with the base shell such that upon mounting of the reflector lamp the holder and the base shell fix one another reciprocally through the cooperation of the metallic holder with the thread of the base shell and with the aid of the depth stop, arranged in the reflector neck, for the metallic holder. During the mounting of the base shell on the metallic holder, the cooperation of the metallic holder with the thread of the base shell exerts a force in the axial direction which tends to reduce the spacing between the holder and the bottom of the base shell. However, the depth stop prevents an axial movement of the holder. A force of the same magnitude, but acting in the opposite direction, is exerted on the base shell. This force likewise tends to reduce the distance between the bottom of the base shell and the holder. After being screwed onto the metallic holder, the base shell is supported on the outer wall of the reflector neck. The outer wall of the reflector neck forms a stop surface for the base shell, and thereby serves as opposing bearing to the depth stop on which the metallic holder rests. In particular, the depth of the screwed connection is determined by the above-named stop surface for the base shell and the above-named depth stop for the metallic holder. This renders it possible to fasten the base shell on the reflector neck without cement. Moreover, owing to its contact with the inner wall of the base shell, the metallic holder offers a simple possibility for making electric contact with the lamp.
The rotationally secure arrangement of the metallic holder in the reflector neck is advantageously ensured by virtue of the fact that both the shape of the cutout in the reflector neck and the section, arranged in the cutout of the reflector neck, of the metallic holder have a shape which is not rotationally symmetrical with reference to the reflector axis, and the dimensions of the cutout and of the section, arranged in the cutout, of the metallic holder, are coordinated with one another. This can be implemented in a simple way by virtue of the fact that the section, arranged in the cutout in the reflector neck, of the metallic holder is designed as a sleeve which has at least two mutually opposite side walls running parallel to one another, and the reflector neck has at least two mutually opposite inner walls in the region of its cutout, the side walls of the sleeve bearing against the inner walls. In order to fix the metallic holder in the reflector neck, it is advantageously provided with at least two lugs which are angled off perpendicular to the reflector axis and rest on the shoulder, designed as depth stop, of the reflector neck. The part, projecting from the reflector neck, of the section, arranged in the cutout of the reflector neck, of the metallic holder is advantageously provided with knobs which bear against the inner wall of the base shell and engage in the thread of the base shell. These knobs form a thread coordinated with the thread of the base shell and thereby permit a screwed connection between the base shell and the metallic holder. In order to ensure a backlash-free arrangement of the base shell on the reflector neck, the outer contour of the reflector neck is advantageously provided with a surface running obliquely relative to the reflector axis. In addition, the base shell is advantageously fixed on the reflector neck with the aid of an adhesive or by means of crimping, in order to prevent releasing of the screwed connection between the base shell and the metallic holder. The metallic holder is advantageously also used to make electric contact. For this purpose, one of the supply leads projecting from the lamp is connected in an electrically conducting fashion to the metallic holder. As a result, this supply lead makes electric contact with the thread of the base shell, while the other supply lead is connected in an electrically conducting fashion to the contact plate of the base shell.